This invention relates to a flotation device, and more particularly to a flotation device for veering out a lifeline behind a moving vessel such as a boat or ship.
Lifelines are provided on the decks of ships to be thrown overboard in a xe2x80x9cman overboardxe2x80x9d emergency. Lifebuoys are preferably attached to lifelines so that they are not simply lost when thrown overboard, but lifelines may be attached to flotation devices other than lifebuoys. The purpose of the flotation device, whether a lifebuoy or a smaller buoyant object, is first to give weight to the end of the lifeline enabling it to be thrown from the ship, second to support the trailing end of the line (which will usually be a floating line but which may nevertheless have a tendency to sink when waterlogged), thirdly to make the position of the trailing end of the lifeline visible both from the ship and to the person in the water and in some cases fourthly to provide a buoyant object, such as a lifebuoy, to which the person in the water may cling or even climb into.
The chief difficulty in rescuing a man overboard by means of a streamed lifeline is the danger of running him down in an effort to make the lifeline reach him. A lifeline thrown outwards from a fast moving vessel will immediately adopt a position astern, making it very difficult to bring the line to the person in the water without first running him over. This is particularly dangerous when propellers are running fast, but it may be impracticable to heave to or even slow down appreciably in bad weather conditions not only because of danger to the vessel but because the person in the water might separate and be lost from view.
An object of the present invention is to provide a flotation device which will veer a lifeline away from a moving vessel to one side, making it relatively easy to steer the line across the person in the water without bringing the vessel dangerously close. Provided he is able to grasp the line it does not greatly matter if he cannot immediately reach the flotation device, so that the further the device is veered to one side of the vessel the less accurately the latter has to be manoeuvred. Once the person in the water has got hold of the line he can then move along it either to the flotation device or to the vessel itself.
Flotation devices which will veer a line away from a moving ship are used, for example, in minesweeping and in sea fishing, where they are known as otterboards. However a relatively small, lightweight flotation device such as is stored on deck with a lifeline is vulnerable to being flipped over by the action of wind or waves.
A principal object of the present invention is to provide a flotation device which will continue to veer in the same direction whichever way up it lies in the water. It is thus possible to provide a small, compact, lightweight device which will not present storage and handling problems even when fitted on the deck of a relatively small sailing or motor boat.
In accordance with the present invention there is provided a flotation device for veering out a lifeline behind a moving vessel, comprising at least one first keel member angularly related to at least one second, oppositely projecting keel member, the device being adapted to float with only one of said first and said second keel members normally in the water, the other of said first and second keel members normally upstanding above the water surface, and a point of attachment for the lifeline in an outwardly-opening angle between and in the region of leading ends of said keel members, such that when towed the device will tend to veer in the same direction whichever of said keel members is in the water.
Said point of attachment may be on or near the periphery of a base of the device from opposite sides of which said first and second keel members project, the point of attachment lying on the bisector of an angle of not less than 45xc2x0 between said keel members.
The base may be generally planar and may be ring-shaped.
Said first and second keel members preferably each have sufficient buoyancy to tend to lift the base to or above the water surface. The base and keels may be formed from buoyant material, and/or either or both may have inflatable areas
The device may comprise a plurality of parallel first keel members and a plurality of parallel second keel members angularly related to the first keel members, said point of attachment lying in the outwardly opening angle between outermost of said first and said second keel members.
The point of attachment preferably lies generally at the intersection of lines respectively perpendicular to the, or the nearer, said first and second keel members, said lines intersecting said keel members at points on the latter which are approximately at 25% of the length of the keel member measured from its end nearer to said point of attachment.
Preferred embodiments of the present invention will now be described by way of non-limitative example with reference to the accompanying drawings, in which: